A64-OLinuXino routing completed, but we still have to final touch this and that


A64-OLinuXino

What you see above is the completely routed A64-OLinuXino! Files are push to GitHub as usual.

Now is time to re-check everything and final touch this and that before run the first prototypes.

One issue which we still have not addressed is the dual power supply for MMC card which to allow maximal performance.

We saw there are already patches on Linux-Sunxi for adding this but I do wonder if anyone has try it and if there are already boards with this feature.

There is no problem to add 1.8V and 3.3V mux-ed power supply to MMC card, but which GPIOs to use to enable/disable these?

Any suggestions are welcome!

24 Comments (+add yours?)

  1. Александр Луцай (@SL_RU_Dev)
    Jan 22, 2016 @ 18:45:40

    Awesome :з

    Will be exactly this board used in your laptop?

    Reply

    • Petr Tomášek
      Jan 22, 2016 @ 19:29:53

      A64 is useless for laptop as it doesn’t allows for a LCD and Ethernet (GBit) at the same time!

      Reply

      • adj
        Jan 23, 2016 @ 03:04:23

        Call Samsung, Toshiba, Lenovo, HP, Asus, Acer etc. to tell them that every laptop needs ethernet. Do you really think that every laptop comes with ethernet this days?

  2. OLIMEX Ltd
    Jan 22, 2016 @ 18:48:15

    no, but it will be proto to check everything before modify for the laptop🙂
    I saw your question for the laptop – we have development there but I will blog more abut next week

    Reply

  3. wens
    Jan 22, 2016 @ 18:53:28

    Hi,

    Unfortunately no publicly available boards support MMC signal voltage switch.

    The best way to implement this is a dedicated configurable regulator (from the PMIC) for SD card’s or eMMC’s I/O. Although I suppose a GPIO-based switch/mux
    works as well.

    For EMMC connected to SDC2/MMC2, this means one regulator is responsible for VQMMC (labeled VCCQ on your schematics) (not VMMC), VCC-PC, and the pull-up for SDC-CMD. VMMC, or VCC on your schematics, should still be connected to 3.3V.

    For SD card on SDC0/MMC0, this means one regulator for the pull-ups to D0~D3 & CMD pins, and VCC-PF. VDD on the card should still be 3.3V.

    On the A64, there is no separate VCC-PF. Instead it is grouped with VCC-PB and VCC-PH into VCC-IO. Changing this voltage will create problems for other peripherals using these pingroups. The signal level will be wrong.

    So, for the A64, switching MMC signal voltage is only possible for SDC1 and SDC2.

    About which GPIO to use… I suppose any will do? Having it default to 3.3V will cause less problems. If you can’t make the software support the mux, it will still work.

    It’d be nice if you could keep this in mind when doing new board designs, Allwinner or not, or refreshing old designs.🙂

    I put together a table of what Allwinner SoCs support what SD/MMC configurations:
    http://linux-sunxi.org/User:Wens#SD.2FMMC

    Also note that depending on the card/chip used, you might only see improvements in read speed.

    Thanks!

    Reply

    • OLIMEX Ltd
      Jan 22, 2016 @ 19:00:12

      thanks for the detailed answer, I guess level shifter just for the MMC will do better job than to change whole GPIO port voltage.

      Reply

      • wens
        Jan 22, 2016 @ 19:29:12

        Keep in mind for the SD card, the level shifter must be configurable. SD cards start at 3.3V, and drop to 1.8V after being negotiated.

        eMMCs can start directly at 1.8V I think, if the chip supports it. Merrii’s A80 board designs actually have an option to use 1.8V for VCC-PC and eMMC’s VQMMC. It’s just 1 0R across from 3.3V to the lead, or 1 0R across from 1.8V to the lead, selected at production time, but customizable with a solder iron. If the PC pingroup is only used for eMMC, this is a simple solution.

        Note SD and eMMC operate differently.

  4. LinuxUser
    Jan 22, 2016 @ 20:41:24

    > eMMCs can start directly at 1.8V I think
    It is better to check standards.

    IIRC, 1.8V is OPTIONAL, at least SD/MMC cards, and could only be used after making sure card uses it and negotiating it, but I’m not sure about eMMC. I.e. cards are usually starting at 3.3V and if card is capable of 1.8V, host MAY go for it. And it is obvious 3.3V devices would NOT start properly from 1.8V-only. Most advanced SD interfaces I’ve seen were switching 3.3V to 1.8V on the fly by exposing “regulator” to Linux and reprogramming IO voltage as needed.

    Reply

  5. bib
    Jan 23, 2016 @ 17:49:19

    Gigabit ethernet diff pairs lenght matching, perhaps ? As far as i see they did not.

    Cheers,

    Reply

  6. JUANJO
    Jan 23, 2016 @ 22:19:06

    I would like to ask a question:

    How has it been used miller style 45 in lenght tuning?

    kicad now only has enabled miter style “arc”

    I am sorry for my bad english

    thanks.

    Reply

  7. ssvb
    Jan 25, 2016 @ 21:08:39

    Is it a good idea to have USB1-DRV pulled down (so that USB host VBUS is powered off by default)?

    A practical implication is that this causes troubles for sunxi-bootsetup (a generic device independent installer for Allwinner devices, see [1] and [2]). If we have USB host powered on by default, then the user can connect a USB keyboard and navigate the installer menu. But if USB host is powered off by default, then the installer has to somehow guess a board-specific GPIO to enable the VBUS power, which is unfortunately not universally safe.

    Currently sunxi-bootsetup only supports A10/A10s/A20 hardware, but adding H3 & A64 support is also possible and will provide coverage for quite a number of popular development boards (Orange Pi PC, Pine64, …). This will happen when the mainline kernel gets video driver support.

    PS. sunxi-bootsetup also uses the FEL button as an alternative input method, and it is good that the A64-OLinuXino has it. Still the FEL button is much less convenient to use (compared to a USB keyboard).

    [1] http://lists.denx.de/pipermail/u-boot/2015-January/202309.html
    [2] https://github.com/ssvb/sunxi-bootsetup/releases/tag/20141215-sunxi-bootsetup-prototype

    Reply

  8. Booli
    Jan 26, 2016 @ 11:52:25

    Instead of using the LCD or Gigabit Ethernet, why not promote the MiPi – DSI connection and have a MiPi display on sale too?

    Reply

  9. LC
    Jan 26, 2016 @ 23:26:30

    I think you could develop and sell a card with “paranoid” mode. A lot of people would like to have a smartphone with full control. So, maybe it’s not possible to build a small smartphone but even I could have something that I could cut with a physical button : wifi, bluetooth, gps, camera, microphone, and clear the memory with a button ! Charge a clean OS from a second card, protected card. You sell a lot of cards, great, but people need kits, the kit must contain all necessary to have at final a smartphone. A let the possibility a add IO interface. I think a standard version of Linux is better (look at Intel processor). etc.
    Ludovic

    Reply

  10. tudor
    Jan 27, 2016 @ 03:51:01

    could you add a camera interface?

    Reply

    • OLIMEX Ltd
      Jan 28, 2016 @ 09:11:36

      all signals are on the connectors, so if one wants to add will be easy, no space for camera on the current layout

      Reply

      • tudor
        Feb 01, 2016 @ 23:01:53

        would a CSI type interface be possible for your laptop?
        It would give a standard interface for everyone who buys your laptop. If you put a USB camera we will probably get only a 640x480x30fps uncompressed stream and mjpeg/h264 for more.

  11. Matej
    Jan 27, 2016 @ 13:03:15

    What will be exact specs and price for A64?

    Reply

  12. JUANJO
    Jan 28, 2016 @ 14:09:19

    I would like to ask something:

    Do the lenght tunning style you used was with 45° corners?
    My KiCAD version have only the “arc” style enabled.

    Sorry for my bad english, hope you can get my question.

    Thanks.

    Reply

    • SK
      Jan 28, 2016 @ 17:17:31

      The DDR lines seem to be done with “arc”?

      Reply

      • JUANJO
        Jan 28, 2016 @ 19:59:16

        “If you download Github project you will can see that the corners are done in 45°, is not the first project i have seen they make the length tuning with that feature on KiCAD, and i would like to know how they do it, since it’s not available yet.”

  13. Trackback: Quark LIX .::. Foro KiCad en castellanoELEKTROQUARK

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